Phytone per se, an isoprenoid ketone identified by G.C. and mass spectrae Analyses as having a 6, 10, 14-trimethylpentadecan-2-one skeleton, is a composition which has been found in nature. It has been found in marine algae, and lavender oil. It has also been found to be a component of a male crab, Carcinus maenas, androgenic glands functioning as an inhibitor of ovarian vitellogenesis. This molecule however has never before, insofar as known, been disclosed as showing biological activity against insects.
Natural materials, and compositions that modify insect behavior via one type of biological activity or another have been known for many years. For example, host selection by phytophagous insects is known to be mediated principally by secondary plant metabolites. Both larval and adult insect herbivores are responsive to a variety of plant chemical stimuli. Phagostimulants and deterrents are thought to provide the bulk of the information that govern choice of food plant and host suitability, and hence crop plants with defined allelochemic profiles has been recognized, and at times manipulated in insect pest management. Although, over the last two decades, much activity has been directed to chemical work on the isolation and identification of a wide array of biologically active natural products which in some way affect the behavior, development or reproduction of insect pests, agricultural scientists yet depend largely on traditional methods for selecting adequate yield properties. Even though highly active allelochemicals have been identified, only in relatively limited situations has chemical guidance been a leading factor in screening for biological properties.
Environmental concerns nonetheless circumscribe the present use of insecticides, and accordingly there is an increasing need to limit the amount and kinds of insecticides which are applied to crops; if not a need to limit the use of insecticides entirely. Hence there is a present need for biologically active products derived from nature for regulating and controlling the populations of insect herbivores, notably insect graminivores. Such products are generally valuable because they are not normally harmful to the environment, and they are biodegradable.